As previously reported by my colleague Lynn Grayson, ExxonMobil has faced a recent onslaught of scrutiny over allegations that fossil fuel companies had committed fraud by downplaying the effect of climate change on their businesses. These matters include a subpoena issued by the U.S. Virgin Islands’ Attorney General’s office related to allegations of violating two state laws by obtaining money under false pretenses and conspiring to do so; and New York Attorney General Schneiderman’s investigation where documents have been subpoenaed to determine whether the company misled investors about the dangers climate change posed to its operations.

Two events last week suggest that this fight will not end anytime soon.

ExxonMobil filed suit in the Northern District of Texas, seeking an injunction barring the enforcement of a civil investigative demand issued by the Massachusetts Attorney General to ExxonMobil, and a declaration that this demand violates ExxonMobil’s rights under state and federal law, including the First and Fourteenth Amendments to the Constitution, as well as the Dormant Commerce Clause.

The Attorneys General of 13 states wrote a sharply-worded letter to their colleagues, noting that “this effort by our colleagues to police the global warming debate through the power of the subpoena is a grave mistake” and “not a question for the courts.” The letter outlines how this investigation is in fact “far from routine” because of its following three characteristics: “1) the investigation targets a particular type of market participant; 2) the Attorneys General identify themselves with the competitors of their investigative targets; and 3) the investigation implicates an ongoing public policy debate.”